1. Field of the Invention
This disclosure relates to a pneumatic cylinder and, more particularly, a single-acting, desirably low-friction pneumatic cylinder for use on a locomotive platform.
2. Description of Related Art
Pneumatic cylinders typically include a cylinder body and a piston and rod assembly to transmit a force and displace the piston and rod assembly. In particular, single-acting pneumatic cylinders admit air pressure on a pressure side of the cylinder body to move the rod and piston assembly with a force generally proportional to the air pressure acting on the piston.
For example, U.S. Pat. No. 5,630,354 discloses a brake cylinder having a brake cylinder body, a head casing, a piston and rod assembly, and a push rod assembly. The piston and rod assembly includes a hollow piston rod having a diaphragm piston head at a closed end thereof. A release spring is concentrically disposed about the hollow piston rod between first and second spring seats. The push rod assembly has a socket end and a coupler end. The socket end inserts within the hollow piston rod via an open end and the coupler end couples to brake rigging.
U.S. Pat. No. 2,930,606 to Trümper discloses an axle supported on a vehicle frame by two piston rods with opposed ball-shaped heads. Each rod rests on a piston which slides in cylinder. A conduit leads from each cylinder to a common connecting conduit. Another conduit branches from the connecting conduit leading to a pressure space in which a piston slide valve operates and in which a column of spring washers or an air spring may be disposed. In operation, the weight of the vehicle compresses pressure liquid in the cylinder and this in turn compresses the springs. The piston cylinder in the Trümper patent operates with a liquid rather than pneumatic pressure.
U.S. Pat. No. 1,295,644 to Ver Planck discloses a piston cylinder operable for supporting a vehicle body on a truck. The cylinder piston is pneumatically operated.
U.S. Pat. Nos. 7,243,606; 7,168,370; and 7,185,592, all to Hommen et al., disclose a pneumatic spring for raising the level of the superstructure of a rail vehicle. The Hommen '606 patent discloses a hydro-pneumatic spring that includes a lower pendulum support and a corresponding pressure chamber.
U.S. Pat. No. 4,097,063 to Dean and U.S. Pat. No. 3,786,763 to Pollinger disclose pneumatic spring devices for railway vehicles.
U.S. Pat. Nos. 2,018,312 and 1,958,489 to Moulton disclose a shock-absorber unit that operates as a double-acting piston cylinder shock absorbing arrangement.
U.S. Pat. No. 1,201,622 to Putnam discloses a four-piston cylinder arrangement for shock-absorbing purposes in a rail vehicle.
U.S. Pat. No. 444,182 to Robinson discloses an air spring device wherein a piston and a cylinder each have a ball-socket connection for connection to a truck frame on one side and an equalizer on the other.